1. Field of the Invention
The present invention relates to novel cephalosporin derivatives for oral administration, and more particularly to cephalosporin derivatives and their non-toxic salts showing excellent antibacterial effect by oral administration.
2. Description of the Prior Art
Cephalosporin drugs are widely used for the treatment and prevention of various infectious diseases caused by pathogenic bacteria.
Especially, since the cephalosporin drugs for oral administration, represented by cefalexin, can be more easily used than the one for injectional administration, they are most widely used now. Furthermore, the compounds having an alkylthio group at the 3-position of cephalosporin derivative are disclosed more recently (U.S. Pat. No. 4,452,851).
However, known cephalosporin drugs for oral administration are much inferior to the one for injectional administration in terms of antibacterial activity and antibacterial spectrum, and the problem is the remarkable increase of strains resistant to these drugs.
Under such circumstances, it is desired to find cephalosporin drugs having excellent antibacterial activity, wide antibacterial spectrum, and effective amount in the blood concentration.